| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1970 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | -4.07 | a | -6.22 | g | -29.70 | a | -16.88 | j |
| 1971 | -51.33 | d | -35.18 | -35.00 | u | -13.14 | b | 26.87 | a | 44.29 | i | 43.00 | x | 36.47 | a | 28.93 | c | -6.77 | a | -17.86 | b | ----- | z | -4.00 | d | |
| 1972 | -38.45 | b | -33.90 | -32.39 | 0.33 | ----- | z | 41.83 | 42.90 | 37.11 | v | 24.00 | b | 13.52 | b | ----- | z | -22.74 | -0.54 | c | ||||||
| 1973 | ----- | z | -33.00 | ----- | z | 3.90 | 29.10 | 38.77 | ----- | z | 33.39 | 24.85 | c | 1.81 | -25.66 | a | -17.87 | 6.14 | c | |||||||
| 1974 | -37.06 | -47.29 | -20.87 | 5.40 | 25.55 | b | 38.56 | c | 44.23 | i | 42.52 | ----- | z | 6.45 | b | -15.20 | -25.26 | -2.72 | b | |||||||
| 1975 | -27.57 | a | -11.00 | a | -2.77 | 5.53 | ----- | z | 42.67 | 49.13 | 42.29 | 30.97 | 10.90 | -15.57 | -23.76 | b | 9.17 | a | ||||||||
| 1976 | -16.26 | -26.90 | -2.58 | 16.60 | 33.35 | 47.40 | 47.52 | 42.45 | 31.53 | 13.39 | 5.41 | a | -13.23 | 14.89 | ||||||||||||
| 1977 | 0.58 | -1.25 | -14.97 | ----- | z | 31.13 | 42.43 | 44.42 | 42.65 | 28.24 | a | 10.10 | -15.77 | -19.87 | 13.43 | a | ||||||||||
| 1978 | -1.97 | -9.21 | -5.16 | 13.57 | 29.77 | a | 41.23 | 45.90 | 39.45 | 31.43 | 6.29 | -3.03 | -11.29 | 14.75 | ||||||||||||
| 1979 | -9.48 | -33.61 | -6.39 | 9.03 | 33.94 | 42.23 | 45.48 | 44.35 | 28.77 | 19.81 | 8.57 | -28.00 | 12.89 | |||||||||||||
| 1980 | -24.90 | -4.14 | -0.65 | 14.57 | 36.45 | 42.70 | 46.90 | 37.87 | ----- | z | ----- | z | ----- | z | ----- | z | 18.60 | d | ||||||||
| 1981 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1982 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1983 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1984 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1985 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1986 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1987 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1988 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1989 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1990 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1991 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1992 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1993 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1994 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1995 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1996 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1997 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1998 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1999 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2000 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2001 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2002 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2003 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2004 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2005 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2006 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2007 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2008 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2009 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2010 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2011 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2012 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2013 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2014 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 2015 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 27.50 | x | 14.30 | h | -1.27 | -22.31 | b | -11.79 | j | |
| 2016 | -7.97 | -10.43 | v | ----- | z | ----- | z | 35.69 | r | ----- | z | ----- | z | ----- | z | 30.38 | v | 8.03 | -11.25 | b | -18.10 | a | -7.32 | h | ||
| 2017 | -6.41 | n | -4.00 | x | -29.48 | f | 5.10 | a | 30.10 | a | 39.31 | a | 46.07 | d | 39.13 | 32.10 | 16.37 | a | -10.24 | a | 6.90 | k | 24.74 | d | ||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | -21.44 | -23.55 | -10.72 | 6.09 | 30.69 | 41.71 | 46.04 | 40.06 | 28.98 | 7.99 | -9.26 | -21.10 | 14.18 | |||||||||||||
| S.D. | 17.29 | 15.79 | 11.16 | 8.54 | 3.46 | 2.58 | 1.90 | 3.42 | 2.93 | 7.91 | 10.49 | 5.74 | 1.12 | |||||||||||||
| SKEW | -0.30 | 0.16 | -0.99 | -0.96 | 0.15 | 0.79 | -0.05 | -0.64 | -0.66 | -0.50 | 0.34 | 0.24 | -0.69 | |||||||||||||
| MAX | 0.58 | -1.25 | -0.65 | 16.60 | 36.45 | 47.40 | 49.13 | 44.35 | 32.10 | 19.81 | 8.57 | -11.29 | 14.89 | |||||||||||||
| MIN | -51.33 | -47.29 | -32.39 | -13.14 | 25.55 | 38.56 | 42.90 | 33.39 | 24.00 | -6.77 | -25.66 | -29.70 | 12.89 | |||||||||||||
| YRS | 10 | 10 | 8 | 10 | 9 | 10 | 8 | 10 | 9 | 12 | 11 | 11 | 3 | |||||||||||||